This application claims priority to International Application No. PCT/DE99/02948 which was published in the German language on Sep. 17, 1999.
The invention relates to a system for supplying power, and in particular, to a system for supplying power to a load connected to a power supply network.
U.S. Pat. No. 5,329,222 describes a power supply to a load connected to an electrical power supply network, for an additional voltage to be supplied in series between the power supply network and the load when the voltage of the power supply network falls or fails. The additional voltage is in this case is supplied in series via a series transformer, also referred to as series-path transformer. In this case, the transformer is supplied with power from an energy store.
A similar arrangement, in which the assisting energy is supplied in parallel, is known from U.S. Pat. No. 5,514,915. This arrangement is also referred to as xe2x80x9cbeing shunt connectedxe2x80x9d. A problem with this arrangement is that, in the event of a fault in the power supply network, energy or volt-amperes may flow into the power supply network fault rather than into the load.
A system in which the present electrical voltage drops on a power supply line are compensated for by emission of a voltage is known from Japanese Patent Abstracts: E-747, 1989; Vol. 13/No. 168, JP 64-1434. The systems comprises a converter which is connected in series via a transformer to a power supply line which connects an energy source to a load. The transformer has two windings, one of which windings is connected in series in the line. If the voltage on the power supply line falls, the converter is started, with electrical power being drawn from a DC voltage source, which is not shown in any more detail, and being emitted via the transformer as the voltage to the power supply line.
A system for assisting the supply of power to a load connected to a power supply network which, while being coupled in parallel to the load, is largely decoupled from the power supply network.
The invention provides for the energy store to be connected in series with the second winding to the load-side end of the first winding, with the two windings having magnetic fields which counteract one another with the same current flow direction with respect to the load. This results in decoupling in the same manner as that of a duplex inductor.
This results in the impedance between the arrangement and power supply network being considerably greater than the impedance between the apparatus and the load, thus effectively resulting in the arrangement and the power supply network being decoupled. In the process, mutual interactions are kept low, and the supply voltage can be kept stable for the load.
Duplex inductors are known from the prior art. In the prior art, they are also referred to as current dividers, current divider induction coils, equalization or compensation inductors or smoothing inductors with a center tap. The use of duplex inductors for on-board power systems on ships is known from the literature reference xe2x80x9cNetzgestaltung mit Duplex-Drosselnxe2x80x9d, STG Symposium at FA Elektrotechnik, on Apr. 16, 1997, Bremerhaven, authors W Planiz and W Schild.
A use of duplex inductors in which power is distributed from one or more feeders to two network elements is known from the literature reference xe2x80x9cModerne Bordnetzkonzeptexe2x80x9d, Shipyard Manual, Vol. XXI, pages 66-67, 1992, Schiffahrtsverlag Hansa. The duplex inductors are designed such that, during normal operation, the two branches of the inductors have currents of such magnitude flowing through them that magnetic effects of the currents are cancelled out.
In one embodiment of the invention, there is a system for supplying power to a load connected to an electrical power supply network. The system includes, for example, an energy store which can be connected via an inductive element having at least two windings to the load, and a first winding connecting the load in series with the power supply network, wherein the energy store is connected in series with a second winding to the load-side end of the first winding, with the two windings having magnetic fields which counteract one another with the same current flow direction with respect to the load.
In one aspect of the invention, the two windings are coupled to one another by means of an iron core.
In another aspect of the invention, the two windings are designed to be approximately the same size.
In still another aspect of the invention, the two windings are connected magnetically in parallel and electrically in parallel but in opposite senses.
In yet another aspect of the invention, the energy store comprises at least one energy-storage element and one coupling appliance.
In another embodiment of the invention, the energy-storage element is in the form of a superconducting energy store, capacitor, battery, flywheel or fuel cell.
In still another embodiment of the invention, the coupling appliance comprises a converter.